It is known in the art to which this invention pertains to provide a suction accumulator between the evaporator and compressor of a refrigeration system, in order to protect the compressor from possible damage. Vaporized refrigerant is received from the evaporator and passed on through the suction accumulator to the compressor. Any raw liquid, generally referred to in the art as "slugs" when admixed with gaseous refrigerant, is metered back to the compressor by the accumulator at a rate that will not result in damage to the compressor. The advantageous results achieved by use of a suction accumulator in a refrigeration system are more fully set forth in my U.S. Pat. No. 3,837,177, to which general reference is made.
While a high measure of success has been attained in metering raw liquid back to the compressor, primarily by provision of a small metering opening in the lower end cap on the stand pipe interiorly of the suction accumulator, a need exists in the art for means for detecting or observing the presence of slugs in the vaporized refrigerant. In this manner, should the volume of raw liquid observed be such that compressor damage is likely, the compressor could immediately be shut down and remedial action taken.